Avoid lookahead

babel · Apr 11, 2021 · 446432f · 446432f
1 parent 6dbf18e
commit 446432f
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Showing 3 changed files with 32 additions and 66 deletions.
diff --git a/packages/babel-parser/src/plugins/typescript/index.js b/packages/babel-parser/src/plugins/typescript/index.js
@@ -194,12 +194,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       return this.match(tt.name);
     }
 
-    tsNextTokenCanFollowModifier() {
-      // Note: TypeScript's implementation is much more complicated because
-      // more things are considered modifiers there.
-      // This implementation only handles modifiers not handled by @babel/parser itself. And "static".
-      // TODO: Would be nice to avoid lookahead. Want a hasLineBreakUpNext() method...
-      this.next();
+    tsTokenCanFollowModifier() {
       return (
         (this.match(tt.bracketL) ||
           this.match(tt.braceL) ||
@@ -211,6 +206,15 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       );
     }
 
+    tsNextTokenCanFollowModifier() {
+      // Note: TypeScript's implementation is much more complicated because
+      // more things are considered modifiers there.
+      // This implementation only handles modifiers not handled by @babel/parser itself. And "static".
+      // TODO: Would be nice to avoid lookahead. Want a hasLineBreakUpNext() method...
+      this.next();
+      return this.tsTokenCanFollowModifier();
+    }
+
     /** Parses a modifier matching one the given modifier names. */
     tsParseModifier<T: TsModifier>(allowedModifiers: T[]): ?T {
       if (!this.match(tt.name)) {
@@ -548,8 +552,8 @@ export default (superClass: Class<Parser>): Class<Parser> =>
     }
 
     tsParseTypeMemberSemicolon(): void {
-      if (!this.eat(tt.comma)) {
-        this.semicolon();
+      if (!this.eat(tt.comma) && !this.isLineTerminator()) {
+        this.expect(tt.semi);
       }
     }
 
@@ -603,6 +607,9 @@ export default (superClass: Class<Parser>): Class<Parser> =>
           this.raise(node.start, TSErrors.ReadonlyForMethodSignature);
         }
         const method: N.TsMethodSignature = nodeAny;
+        if (method.kind && this.isRelational("<")) {
+          this.raise(this.state.pos, TSErrors.AccesorCannotHaveTypeParameters);
+        }
         this.tsFillSignature(tt.colon, method);
         this.tsParseTypeMemberSemicolon();
         if (method.kind === "get") {
@@ -633,33 +640,6 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       }
     }
 
-    tsParseMethodSignatureKind(node: any) {
-      if (!this.isContextual("get") && !this.isContextual("set")) {
-        return;
-      }
-      const kind = this.state.value;
-      if (
-        this.tsTryParse(() => {
-          if (this.tsNextTokenCanFollowModifier()) {
-            // Check if a property is a method signature
-            const lookahead = this.lookahead();
-            if (lookahead.type === tt.parenL) {
-              return true;
-            }
-            if (lookahead.type === tt.relational && lookahead.value === "<") {
-              this.raise(
-                this.state.pos,
-                TSErrors.AccesorCannotHaveTypeParameters,
-              );
-              return true;
-            }
-          }
-        })
-      ) {
-        node.kind = kind;
-      }
-    }
-
     tsParseTypeMember(): N.TsTypeElement {
       const node: any = this.startNode();
 
@@ -701,8 +681,16 @@ export default (superClass: Class<Parser>): Class<Parser> =>
         return idx;
       }
 
-      this.tsParseMethodSignatureKind(node);
       this.parsePropertyName(node, /* isPrivateNameAllowed */ false);
+      if (
+        !node.computed &&
+        node.key.type === "Identifier" &&
+        (node.key.name === "get" || node.key.name === "set") &&
+        this.tsTokenCanFollowModifier()
+      ) {
+        node.kind = node.key.name;
+        this.parsePropertyName(node, /* isPrivateNameAllowed */ false);
+      }
       return this.tsParsePropertyOrMethodSignature(node, !!node.readonly);
     }
 

diff --git a/packages/babel-parser/test/fixtures/typescript/interface/get-set-properties/output.json b/packages/babel-parser/test/fixtures/typescript/interface/get-set-properties/output.json
@@ -1,10 +1,6 @@
 {
   "type": "File",
   "start":0,"end":55,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":1}},
-  "errors": [
-    "SyntaxError: Missing semicolon (2:5)",
-    "SyntaxError: Missing semicolon (3:5)"
-  ],
   "program": {
     "type": "Program",
     "start":0,"end":55,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":1}},
@@ -25,23 +21,14 @@
           "body": [
             {
               "type": "TSPropertySignature",
-              "start":18,"end":21,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":5}},
-              "key": {
-                "type": "Identifier",
-                "start":18,"end":21,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":5},"identifierName":"get"},
-                "name": "get"
-              },
-              "computed": false
-            },
-            {
-              "type": "TSPropertySignature",
-              "start":22,"end":34,"loc":{"start":{"line":2,"column":6},"end":{"line":2,"column":18}},
+              "start":18,"end":34,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":18}},
               "key": {
                 "type": "Identifier",
                 "start":22,"end":25,"loc":{"start":{"line":2,"column":6},"end":{"line":2,"column":9},"identifierName":"foo"},
                 "name": "foo"
               },
               "computed": false,
+              "kind": "get",
               "typeAnnotation": {
                 "type": "TSTypeAnnotation",
                 "start":25,"end":33,"loc":{"start":{"line":2,"column":9},"end":{"line":2,"column":17}},
@@ -53,23 +40,14 @@
             },
             {
               "type": "TSPropertySignature",
-              "start":37,"end":40,"loc":{"start":{"line":3,"column":2},"end":{"line":3,"column":5}},
-              "key": {
-                "type": "Identifier",
-                "start":37,"end":40,"loc":{"start":{"line":3,"column":2},"end":{"line":3,"column":5},"identifierName":"set"},
-                "name": "set"
-              },
-              "computed": false
-            },
-            {
-              "type": "TSPropertySignature",
-              "start":41,"end":53,"loc":{"start":{"line":3,"column":6},"end":{"line":3,"column":18}},
+              "start":37,"end":53,"loc":{"start":{"line":3,"column":2},"end":{"line":3,"column":18}},
               "key": {
                 "type": "Identifier",
                 "start":41,"end":44,"loc":{"start":{"line":3,"column":6},"end":{"line":3,"column":9},"identifierName":"bar"},
                 "name": "bar"
               },
               "computed": false,
+              "kind": "set",
               "typeAnnotation": {
                 "type": "TSTypeAnnotation",
                 "start":44,"end":52,"loc":{"start":{"line":3,"column":9},"end":{"line":3,"column":17}},

diff --git a/packages/babel-parser/test/fixtures/typescript/interface/get-set-type-parameters/output.json b/packages/babel-parser/test/fixtures/typescript/interface/get-set-type-parameters/output.json
@@ -2,8 +2,8 @@
   "type": "File",
   "start":0,"end":58,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":1}},
   "errors": [
-    "SyntaxError: An accessor cannot have type parameters. (2:9)",
-    "SyntaxError: An accessor cannot have type parameters. (3:9)"
+    "SyntaxError: An accessor cannot have type parameters. (2:10)",
+    "SyntaxError: An accessor cannot have type parameters. (3:10)"
   ],
   "program": {
     "type": "Program",
@@ -26,13 +26,13 @@
             {
               "type": "TSMethodSignature",
               "start":18,"end":39,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":23}},
-              "kind": "get",
               "key": {
                 "type": "Identifier",
                 "start":22,"end":25,"loc":{"start":{"line":2,"column":6},"end":{"line":2,"column":9},"identifierName":"foo"},
                 "name": "foo"
               },
               "computed": false,
+              "kind": "get",
               "typeParameters": {
                 "type": "TSTypeParameterDeclaration",
                 "start":25,"end":28,"loc":{"start":{"line":2,"column":9},"end":{"line":2,"column":12}},
@@ -57,13 +57,13 @@
             {
               "type": "TSMethodSignature",
               "start":42,"end":56,"loc":{"start":{"line":3,"column":2},"end":{"line":3,"column":16}},
-              "kind": "set",
               "key": {
                 "type": "Identifier",
                 "start":46,"end":49,"loc":{"start":{"line":3,"column":6},"end":{"line":3,"column":9},"identifierName":"bar"},
                 "name": "bar"
               },
               "computed": false,
+              "kind": "set",
               "typeParameters": {
                 "type": "TSTypeParameterDeclaration",
                 "start":49,"end":52,"loc":{"start":{"line":3,"column":9},"end":{"line":3,"column":12}},